#回文数
# def judge( str ):
#     if not str:
#         return False
#     i,j = 0,len(str)-1
#     while i<j:
#         if str[i]!=str[j]:
#             return False
#         i += 1
#         j -= 1
#     return True
# m = judge("abcdef")
# print(m)
#最大公约数
def ha(a, b):
    if a % b ==0:
        return b
    else:
        return ha(b, a % b)
m = ha(3, 6)
print(m)

